The overall goals of this project are to investigate the character of the relatively steady electrical fields that are produced by endogenous currents in injured vertebrates, and to clarify the role of such fields in initiating and controlling nerve regeneration. We plan to study in vivo the effect of modulating endogenous currents on the growth of nerve during the early stages of limb regeneration in urodeles, and in regenerating tail tips of Xenopus larvae. We also will study the effect of imposed fields on the growth of neurites in cell culture. In order to better understand the character of the endogenous fields generated in regenerating urodel limbs, we will map them internally. As derivative of these studies, we would expect to learn how, in some measure, to speed and perhaps guide nerve regeneration by modulating endogenous fields, as well as by imposing artificial ones.